On the down side, there's no work/life balance. The HR people like to claim that they value and promote a work/life balance, but the reality falls FAR short. (Maybe the HR team is treated differently?) The people who work on the technical side of things put in long hours and are often expected to give up weekend time. Some are called in the middle of the night and expected to work on middle of the night fixes even if they put in a 10 hours the day before and have another 10 hour day waiting for them the next day.
If you have to travel, they freely take your personal time. You can expect to give up your weekend to travel to your destination and another day or two of your weekend when you travel back. If you have a weekend at the destination, you will likely be expected to give up another weekend day to work. If you think you'll be provided with 6 days of vacation add-back to make up for the 6 off days of home/off days you missed, you are sadly mistaken. If your boss is feeling extra generous, you might get 1. No matter how much of a time difference you have to recuperate from, you will be expected back at work on the Monday after your trip. So your 2-week travel for work with a week of work preceding it and immediately following it means you'll essentially be working for a month straight. (Granted, possibly minus the ONE Sunday.) And they wonder why people quit.
Just like 90% of employers nowadays, they burn people out and work them to death. Do they pay well? Yeah. Might you get a bonus? Yes. But really, at a certain point, time is much more valuable than extra money. People are left with almost no time to live a life, to have friendships or spend time with their families. When you're exhausted, overworked and stressed out, the little time you have off ends up being spent on chores and errands and collapsing to do nothing with whatever little time is left.
Another big issue is the project management process. It's a disaster. Managers throw around the words "agile" and "scrum" but these processes have never been implemented. Upper management defines deadlines before the scope of work has even been defined. This ends up causing a lot of the aforementioned issues (long hours, stress, people leaving).